I would just take my time until I found a good OLDER pump gun. I don't think much of what is new on the market. My 20/16 pump gun list would be:
Model 12 Win (not Nickle steel 1912) short grooved flat bottom forend
Model 31 Rem preferably Lt over standard
Model 37 Ithaca (older model with ser# on front of receiver and on the barrel)
Model 17 Rem like Ken mentioned (only one extractor compared to 37 that has two)
G2
