What motor did I just recieve?

I agree Theon. This jug has bigger ports and better overall quality despite the raggedy fins.
I plan to port this one with wider ports, some transfer lip removal and slightly higher exhaust port with piston skirt trimmed for full intake duration.
The motor is brand new and simply requires a front motor mount hole to be drilled out larger and re-tapped. I have not dejugged it yet, but the head looks a bit better as well, hopefully it has the "squish band" mod...
I'm favorably inclined from outside inspection!

Centering the exhaust port is one of my first mods, widening it by a good few mm.
I do not lift the exhaust much, unless I'm after 10 000 RPM, and then not much. As lifting exhaust lowers effective capacity and compression.
Inlet will only need a couple of mm cut on piston for best results, easily over done!
I run these barrels with a .2mm base gasket without lifting ports or ramping pistons. As the port timing is near ideal for good all round riding.
Inlet is widened a couple of mm,
I also flatten the transfer roofs, in both directions.
Getting the charge to flow across the piston dome, better for higher comp.
I then will usually get a nice squish with a standard head gasket and 40mm crank, but they're all different!

Yeah, exactly what I was thinking since I HATE light switch powerbands, especially on a single speed bike! The old style small intake 66cc I just ported is nice and fat from right off idle, just how I like them! No real port timing changes, just wider on both ports
and removed the ridge from transfers.