I had a Bultaco Sherpa T trials 350 (326cc) and it was a bit different from this. They had a one piece tank side covers and seat, all very light and flimsy. This one could be and older trials bike or a combo of several Bultaco dirt models. Mine looked the the pic below.
My brother was a sub dealer for Bultaco, so I bought a lot of different models over the years. They were a great bike in their day. I think I had one of each model, except the 360 El Bandito. He raced a new Pursang every year. All nice