I'm looking at a defunct regulator on my desk (my very first, actually) that's an M3, which is a Milwaukee clone (or, possibly, vice versa). The only marking at all on the regulator itself is the knob, which is removable.
The original AquaticLife regulator was a re-painted Aquatek, and they sold it for an extra $50 or $75. The paint job and the new label on the front changed nothing except the price tag.
Anyway, no worries on the aesthetic differences. Many of the quality regs we use are rebranded. In fact, Airgas, which is a relatively popular brand, doesn't even manufacture their own regs. They rebrand other manufacturers' regs. The same with Linde. They give them new model numbers, sometimes new gauges, and screw on a new knob. Heck, I have a couple old Matheson model 8 regulators that were rebranded by Craftsman and Hewlett Packard.
The slight aesthetic differences in yours may result from a different factory making individual pieces, or a slight intentional tweak in design.
As for the solenoid, the coil and DIN connector look similar, if not identical. It's only the mount that changed, and that has no moving parts.
Again, no worries unless it doesn't work.