Call Mohawk and ask them. You have the serial # which they should be able to quickly convert to date of manufacture. 1 Mohawk = 3 of anybody else's lift with respect to build quality.
As suggested above give Mohawk a call and they can get you the information you need.
I called the parts dept. at Mohawk this afternoon. The serial number comes back with a 1989 build date.That US patent was granted on 1985, so maybe your leading 89 is the year made.
US4500071A - Dual hydraulic lifts - Google Patents
A dual lift for large loads such as vehicles has two lifting units set in opposition to each other to straddle the load. Each of the lifting unit has a vertical standard, cantilevered arms mounted on the standard for movement therealong, and a hydraulic actuator for raising and lowering said...patents.google.com
