Sure looks like a hammer (the "barrel cover" is a later aftermarket or home made addition or course). Though a few issues. All Hammer A's I've seen have been silver. Also, all had "Hammer paintball cal 68" on the grip frame, not "Paintball Sports".
There was at least one clone of the Hammer made in China (called the S-1)...
... and I seem to remember there being at least one other clone out there. I'll dig a bit more tomorrow.