"Pino" definitely can mean a car lift in PR; for example:
"Taller de mecánica con 1855 pc, En el barrio de Buena Vista; 2 baños, almacén y oficinas, incluye un pino de levantar autos."
"Tambien cuenta con taller de lavar carros dealer, Pino para levantar autos etc."
http://puerto-rico.clasificados.com/bienes-raices/pino-para-...
The location of the VIN (if that's what they were looking for) varies according to the vehicle. I admit it's not usually underneath, but perhaps it could have been engraved there as an anti-theft measure. Anyway, I think your first idea was probably right, and it's difficult to see what else this could mean. "Lo" would refer to the "auto", of course.
The translation workplace 
peer agreement (net): +1
