Yes, it is quite rare.
Playtron only made 2 electric buggies in the mid 80's, the 2wd Doberman, and the 4wd Lynx (I have a Lynx)
The Doberman is basically a 2wd version the Lynx, sharing the same chassis, suspension, body, gearbox etc.
Only the front wheels/tyres and a few other bits on the front end are different.
Most 2nd hand editions always seem to have the front bumper missing, as it usually was the first thing to break!
Your car has the bumper in tact which is excellent. If you are not a collector and want to put it on ebay I'm sure you'll get a decent price.
For more info, go to the tamiya club website here