There are already several dozen members in the "40 years" and "50 years" line-ups, which are displayed (in photos of them all getting a trim) on the walls of his barber shop, which is today a nostalgic and colourful room at his home.
When he was a lad of 15 he was tossing up whether to be a cabinet maker or a barber. "My father was a farrier in Hastings, but that looked like hard work to me."
Through word of mouth he heard there might be an apprenticeship going with Des Rae, who ran a successful barber shop and tobacconists in the town, and made the approach.
He got taken on - for a four-year, 10,000-hour "learn the trade" stint.
"In the early days I scrubbed the floors and the walls, washed the windows and swept the footpath outside," he said, adding it was typical of the way jobs were in the early 50s where you "worked your way up."
Which is what he did.
Des Rae was a good boss, he said, who taught him a working philosophy he has never forgotten.
"He told me the most important person around is the person who walks in the door.
"He'd say 'you're not doing them a favour - they are doing you a favour'."
Only a teenager, he was not nervous wielding the sharp scissors on chaps who trusted their ears to him, but confessed the first time he did a shave, with a very sharp razor, he had the old butterflies.
"The chap's name was Chow Turnbull, I still remember it. He had a very dimpled face and that made it difficult."
But he added with a smile that no blood was spilled.
When Des Rae closed up shop, he went to work for a Mr Donovan, and it was in his stint there he came to possess a slice of barbering history he uses in his small and comfortable shop today.
"They were modernising the shop and they were going to throw an old chair out. It was going to the dump, so I saved the dump a job and grabbed it."
Re-upholstered and its timbers polished up, the 1880-built American "Kochs" chair is still in action.
Mr McFlynn went out on his own after that and had shops firstly in Heretaunga St and then Warren St - the latter for 25 years.
He has always embraced a friendly shop, and a shop where humour is as accessible as a good trim.
On one wall there is a sign which states the $10 prices of a cut. At the foot of it is a note which reads: "Talk politics...$50 surcharge."
Back in those early days he remembers Mr Elliott coming in.
Mr Rae had basically said: "It's all yours - you're on your own."
Was Mr Elliott aware then that he was Mr O'Flynn's first customer?
"No, I had no idea," he said.
Would he still have had the cut if he had known that?
"Oh, I'm not so sure now," he laughed, before adding that through the years and all that clipped hair, he had never gone to anyone else for a trim.
"So it must have been okay because I've always come back...we've gone through life together me and Brian. We've swapped a lot of jokes and a lot of stories."
He has no idea how many haircuts he would have had but it would be in the hundreds.
"I go when my wife tells me I need a haircut."
Mr McFlynn said the early years were basically "short back and sides" and he recalls seeing some children return twice in one day. "Their mums and dads would tell them to get it cut short so I would - but they'd go home and be told it wasn't short enough and they'd come back...I had to take some more off."
When he began the trade there were 17 barbershops in Hastings.
"There'd only be five or six now."
He said the 1970s, when long hair became the fashion, a few barbers went out of business.
But he hung in there, and has kept up with fashions and phases...even to the "spike it and gel please" generation.
So who cuts his hair?
"Oh my wife does, and she's very good, although I asked her once to spike it but she wouldn't," he said, breaking into a grin.
"This one's on the house," he told Mr Elliott during his latest visit.
"But that won't happen again for another 10 years," he added.
"This is more a hobby now, but I have been blessed with good health and I still do a dozen or so a month and have no plans to retire," he said.
As Mr Elliott left he remarked: "See you in 10 years Brian."
Mr McFlynn smiled as he began to sweep the floor.
"Oh I hope so," he said.