idk, theres a few threads on how to find out ratios, but to get an idea you can jack it up, spin the wheel and count how many times the driveshaft turns for each complete turn of the rear wheel.
Ex: if the shaft spins just under 3-1/2 times as the wheel completes one turn, you prob have 3.23s.
If the shaft spins to just past the 3-1/2 mark, you likely have 3.55s
Enjoy the new Scamp!
Then look for a metal tag on one of the cover bolts- it will have the ratio stamped on it. If the tag is missing, jack the rear up and spin the tire, counting the number of times the driveshaft spins, that will give you a close approximation- i.e. 3.23:1. Your other option is to pull the rear cover and look for the stamp on the ring gear.
Just an FWI, if he chooses to do the jack it up and spin the tire method, with 1 wheel off the ground, it requires 2 (two) rotations of that tire to be able to count the drive shaft # of turns, for a quickie axle ratio guess, WITH AN "OPEN" DIFF, with a sure grip, both tires off the ground would be 1 turn of the tire.