Looks like one of the following:
-A latter-day Spirit-700. Older ones (the one I have) have cheaper-looking plastic tables, that look like vinyl, with fake-looking slat-lines molded into them. On mine, the "table" on the left simply lifts-out.
-An early Silver-B
My guess would be late '90s if it's a Spirit.
2001-2003 if it's a Silver-B - somewhere in that range.
Pull the Gas Valve Knobs, take-out the handful of screws that hold the black metal shield with the instructions on it, and look underneath. If you're lucky, that's where you'll find the model and serial number sticker.