Serial Number Location on 2150 2255

I have the opportunity to purchase a one owner 2150 and 2255 from an estate. The oldest daughter contacted me and asked if I would be interested in her late fathers tractors. She sent me photo's and they are complete nice units with cabs and the 2150 has an Oliver self leveling loader and fender tanks. The tractors are located in OK 400 miles from me. I asked her to send me the serial numbers of the tractors but couldn't find the data plates. It's been a few years since I've had an Oliver of that vintage (1855)on the lot and couldn't remember where the plate is located. Looked on tractordata.com and it doesn't show where the plates are located. My question is, where's the data plates so I can tell her where to look.

The 2150 was last run this past Spring and the 2255 has not been started in 2 years (it's a 3208 as seen in photo's). Both of them have 90% rubber with duals. I normally shy away from Oliver's because here in Colorado (I come from Lime Springs, IA 40 miles from Charles City)they weren't very popular and hard to sell, but these units appear to be well taken care of. What would they be worth? I won't keep them, just clean them up and repair as needed, then sell.

Should be under the dash, around where the clutch and brake pedals are. Usually they are covered with dust because nobody cleans that spot if it has a cab on it.

Thanks, now I remember. It's been awhile since I've had an Oliver.