Yeah, when I got my trailer (now 9 years old) a couple of years ago, I don't think the caulking had ever been touched and there were no signs of leaks. Some of the caulk had cracks and gaps in it, so I carefully pulled it off, cleaned everything up, and put fresh caulk on...

It only took a few hours, and I used like 3 tubes of EDPM sealant and some mineral spirits.

Truth be told, I think a lot of trailer builders switched to EDPM more because it is easier for them to ship, store, and handle since it comes in rolls.