Yes indeed, I have the first production model. Ian Beestin, a drummer friend of mine, goes way back with Cliff Brown - I think they were at school together. It was through Ian I got to know Cliff, when he was still at Blackstar and just about to set up 633. Ian was always saying that I should try one of his amps, so when I was able to try the Drive King prototype at a music shop demo I was convinced!
Here's a pic from April 2016 when I went down to Cliff's place to pick up the amp. I brought along my 1x12 cab, the Heritage H150 VSB and Paulman Tele to try it out.