The one time I did a monitor swap like you are describing was easy. I don't recall the size, but I took the bezel off the cabinet with me to Goodwill and just held it against TV's till I found one that seemed right. Got the TV home and de-cased it. The thing dropped right onto the existing mounting bracket like a glove. Exact fit.
So, I'm thinking TV tubes and arcade monitor tubes probably come off the same assembly line.