OK, here goes... I'm attempting to upload pics of the drains and door latches.
That is the same lock that was used on my parents 1970 Bethany pop up, and also the lock that I used to replace the factory latch on my 2000 Scamp! I had to drill new holes in the door, plus fabricate a 'patch' of sorts to cover the old holes. If you are wondering, I found the latch at Hilltop RV, in Fridley, MN, and it cost a lot more than I expected; if I recall, it was over $65.
In my opinion, your lock is far better than the lock Scamp
installs at the factory! With the factory latch, I had to manually close the door; with the new latch, I can 'slam' the door just like every other door.
-- Dan Meyer