First Post Here, I thought you guys might be able to help me out with some info on these two old Yale Forklifts I have

I have two old Yale Forklifts. One we have had for awhile and we call "Big Red" (see why in pictures). The data plate says it is a L5-180-MAS, and it is supposed to be a 18,000 lb capacity lift. We really like it and have had it a couple years. It will easily lift like 20,000 and we have added some extra counterweight in the past to lift almost 24,000. The thing is a BEAST

The 2nd lift we just acquired and to keep them separate we are calling it "Old Yellow". I don't know what the model is or what the S/N is, because there is no data plate. It does look to be a similar body style as the one we already had except the frame is 12" longer in the middle (between the wheels) and about 2" longer behind the rear wheel. Otherwise they seem identical. The measurements on the Mast, Wheels, Tires, etc are all the same. The only other difference is the carriage is 31" which is larger than BIG Red's which is 27 1/2". The other major difference which is great is that someone has setup a side shift and fork positioner on it.

We would like to Fix up this new lift "Old Yellow", but first I would like to find out what the model, capacity, and S/N are. I can't seem to find the S/N anywhere though. I was told by someone that it should be stamped somewhere on the frame, but I can't find it.

Does anyone know where I would find the S/N Serial Number?