Pearce offered several models of speaker cabinets over the years, but I’ve only come across a few 1x12’s.  Here’s a closed back example in black Tolex.  I know that the combo cabinets could be ordered as open or closed back, but all the examples I’ve come across or heard about have included the port, except for one.  Open-back cabinets had two partial back panels and could be converted to closed-back by removing the partial panels and replacing it with a single large panel which used the same screw mounts.  Ironically, the only owner I’ve heard of who ordered the back panels also had the only known (to me) non-ported baffle.