I have a 1986 Azuki Imperial with a rather short stem (50mm). I bought it off of craigslist a year ago, and all of the components apear to be orginal. I am very happy with the bike overall, but want to replace the stem with something a bit longer, around 80mm.

Am I safe in assuming that a stem advertised as fitting a 1" stem and accommodating a 25.4mm handle bar would be the right choice? I have tried measuring, but without a caliper (and with not so good eyesight) it is a bit of a guessing game.