I put a 78 Honda alt on a friend's 71 Land Cruiser in a pinch once, he left it on for 6 years because it was working fine even with the belt alignment off a bit.
If it looks the same externally I'd give it shot since you have it there, the camper doesn't have a high amp alt that I recall because the camper part ran off a separate battery system on those years from what I recall.