Jason, I researched the same issue awhile back. I have a DOT 44 K98icon without a receiver serial. Go to the BATF website and search on the no serial number question. Basically it will tell you that it is not a problem if the gun was made before I believe 1968. There are many (legal) firearms out there without serial numbers, lots of them are latewar K98's and cheap .22's. To remove or alter the serial is another story however and very illegal. Salt Flat