Engine type decode

Hi all,

So I purchased myself a Honda CB750K3 project bike.
The engine and bike were wrecked by the previous owner.
Went on eBay and purchased an "in good condition" according to the seller CB750K2 engine.

Now that I'm slowly building up the bike I wanted to connect a lithium regulator.
But because it did not fit the engine harness (The engine has 8 pin connector and the regulator 6-pin) I contacted Ricksmotorsport.
They told me that I probably purchased myself a Honda Matic engine.. because they have an 8-pin connector.
So now I want to know which engine I have purchased because I'm getting really confused.
Is there an easy way to determine? The engine vin CB750E-2034810

Thanks in advance

The hondamatic is an auto transmission 750, didnt come out till 76 and you would see obvious difference if you look at them side by side. The numbers you have is a K2 standard motor. Post a couple pictures and maybe we can see what you have going on....

1972.