The high gloss finish reminds me that you could get work like this in the 1970s, from some guy selling out of a van on a street corner. He usually carried tapestries and black-velvet Elvises, and cobras poised to strike (that last was the particular piece of "art" that attracted my dad's custom).
Also in the 1970s was a craze for painting plaster statues. My grandmother had one very much like this, only a pug dog. There were finishes you could apply to make the details look antique (the "dirt" in the muscle grooves on the boxer, for example), and spray finishes to create the glossy finish. She taught us all the tricks, and we spent hours at her house painting plaster statues purchased from a plaster statue warehouse nearby, in Decatur, IL. Good times, good times!
Look at the bottom -- my grandmother would never paint over her bottoms, so in her case, you could see the white plaster. I would always paint over mine, so the bottom would be a similar color to whatever color I used on the bottom of the artwork. But over time, the paint and finish chips, and should be able to see bits of white plaster.
If it is hollow and has a ceramic finish, but no other marking, it might be the mass produced sold-out-of-a-van thing. In which case its value would be to collectors of dog memorabilia, probably. It's nicely realistic, and no doubt there's a boxer breeder who is drooling over it right now.