Yes and no. that bike has what look like r6 fork so it would have to ride as a modern, only thing VMX on that is a late Dt 400 motor going on the head so that pre 80,
Really the only vinatge thing on that is the paint scheme. im also prity sure that isnt a Boss frame as carlo never made a high loop so its either a powerDyne or champion (most likely a mx250B champion) or its had the rear loop modified but i doubt it, but if so it would be hard pressed to ride in vintage, then there is the wheels and probally using a flat slide or some other carby too.
There are plenty of US frames over here, depending on what class you rode it in, would depend on your reception. I have a few and never had any problem riding in the right class/era, americans use differant rules so if you follow the Local Dt book youll be welcomed with open arms.