do you have a photo of the 5-pin reg-rec? or a sample photo link from web ?
i assume you mean you have the reg-rec as in "female socket" model, without integrated 5-wires leaving out of it ?
a sample of outlet plug type:
https://www.mikesxs.net/parts/img250/24-2085.jpg
as an sample, what you have is not like this ?
https://www.vmcchineseparts.com/prod...ao-ata250d-atv
http://2120199.cloudcommercepro.com/...phase5wire.png
-"the top 3 pins of the vreg/rectifier are AC in,"
that would be mean 3-phase charge system, 3-phase winding.
and on a chinese, as usual there is no trusting on a "industry std" for wire coloring..
did does "TBoltUSA" database have any pinouts scheamtics ?
they dont have 5-pin reg-rec's listed as shop....when i checked...