Soligors came in many shapes, sizes and from different manufacturers, some were bad, most were good, and some are excellent. In the 135mm I have this version -
Soligor 135mm 2.8 ( M1****** serial number, probably Tokina )
which according to the serial number is made by Tokina. It's a heavy and well made, old thing, but the image quality is excellent, and I like the 'stop down' feature of this series of lenses. There's a big discussion on Soligors in general over on the Manual Focus Forum which is very informative.
The Soligor serial numbers, as best we know, work like this ( the first digit of the lens serial number )
1= Tokina
2= Sun
3= Sun
4= Sun
5= ?
6= Komine
7= Sun
8= ?
9= Kino
31= ?
A= Komura
H4= Kawanon
H5= Komine
H6= Komine
H7= Tokina
H37= Kawanon
M= ?
N= ?
R= ?
T= Tamron
Y= Komura