My model # on the side of the compressor reads 91916734. When I look for parts the only options are model #s 919167340, 919167341, or 919167342. These compressors are 6 hp 150 psi 33 gallon horizontal air tanks and they look the same. The parts list for these compressors are different. Where can I locate the last digit of the model # on a Craftsman compressor?