I agree with Pete; pick up the connectors and a 12V circuit tester before you leave home since you can always return them if they are not needed. How big is the
Scamp? The equipment requirements for the 16' are quite a bit different than the 13'. As Donna indicated, the standard ball for the 13' is 1 7/8 and the 16' is 2". The 13' can use a class A hitch while the 16' requires a B or preferrably a C. Hitch height is 18" to the top of the ball for the 13' and 22" for the 16'
The 16' will require a brake controller (the 13' may not). To fuzzy up things a bit more, Scamp changed the design of the 7-pin connector around 1998 and the original is almost impossible to find. This would require rewiring the trailer connector for a 7-pin Bargman.
I went through the same sort of stuff when we purchased our 99 Scamp 16' in the DC metro area last year... I also made sure I picked it up during the week in case I was still short of parts (or the
tires were so bad I couldn't tow it home).
Get as much info as possible before pick-up. Best of luck with the purchase.