Cliff Christl did a great article on that story a while back on the Packers official website. One of the points made was that whether it was true or not, Lombardi certainly didn't mind the players believing it was true!
Added - here is a link to Cliff's article, which is made from excerpts of oral history interviews with Pat Peppler. In fact, the Twitter post is a direct quote from this article. There is a bit more background that Pat Peppler gave in the article, which I'll cut and paste here:
On whether his duties included more than player personnel: "I did almost all the contract work with Vince. I did what Vince told me to, but I did all the pain in the (butt) stuff. Vince would get into the contracts only with people like Jim Taylor or maybe Bart (Starr) or (Paul) Hornung. The first guy I negotiated with, the first day on the job (in 1963), was (Jim) Ringo. Vince said, 'Get a hold of Ringo,' and offer him this, this and this. Jim said, no. (He wanted) somewhat more; it wasn't outlandish. So I went to Vince and he said, 'Give it to him.' Then later that year, Jerry Kramer was contacted by an AFL team. They were trying to get him to play out his option and offering like $23,000. He was making like $16,000, I think. We had talked to (Kramer) and Vince had offered him like a $1,500 raise. But Vince felt he had to sign Kramer, so he said, 'Get a hold of Ringo for me.' I got Ringo on the phone and Vince told him that he didn't think it was fair that Kramer was going to be making that much more. So Ringo wrote his own contract. Vince gave him $1,000 more after the Kramer thing."
On the negotiations with Ringo in 1964 and whether Lombardi made the deal when Ringo brought an agent with him to Green Bay to negotiate on his behalf: "That was not true. It was a prevalent story and the falsehood that was told -- I think Vince thought it was to his advantage to go along with it."
On what actually happened in the negotiations: "When I called Ringo the next year, before the 1964 season, I had talked to Vince about it. And when I got a hold of Ringo he started to complain about this and complain about that and complain about his contract. I said, 'Wait a minute, Jim. You wrote your own contract last year and the old man gave you $1,000 more than you asked for.' Then he said, 'Give me $25,000 or trade me.' I went to Vince and told him. I said he wants $25,000 or he wants to be traded. I'm sure Vince had already been working on a trade, but he liked to make it seem like he did it snap. Anyway, he gets a hold of Philadelphia, makes the trade and, within an hour, called me back and said he was calling Ringo. No agent."
Here is the link to the full article:
https://www.packers.com/news/pat-pepple ... s-15472243
