That one has the B&S engine as noted by the sideways diamond on the side of the hood. The rear 'pan' sets the age, with the newer models having the foot rest(?) as one part with the transmission cover/seat mount. I'd say it is newer than '97 because they changed color from green to gray after that. I have what I think is a 97 with separate fender/footrest, the one piece being offered later, some in green, and gray being later than that.
By the time they used gray paint, I think the Kohler had been phased out. I haven't seen a gray with a Kohler. Until they went to the Courage series. The hydros and geared drives were available in parallel,. with the hydro costing a few hundred more.
There were to deck control mechanisms also. One with a two-position lever and a dial to adjust the height, and one with a multi-position lever. The second is the later style, and, to my mind provides easier control of the deck as both sides lift equally.
Good ones with a Kohler run from $400 to $600 in Northwest GA area. You can get worn out for less, of course. The steering part is plastic, and does not need lubrication. If you do put lube on it, you will soon have dirt mixed, creating a very fine grinding compound, wearing the plastic quickly.