Many sellers who list the Sogwinder for sale on the "bay" list the name incorrectly. They list the knife as "Sidwinder" or "Sidewinder", but SOG does not make a "Sidwinder"/"Sidewinder" knife based on the catalogs I have seen from years 1989 to the present.
The Sogwinder which you are referring to which has the thumb stud on left side of the blade and with the attachment screw on the right side of the blade is the "Sogwinder I". It is the knife which closely resembles the Sog Stingray with the big difference being the blade style, i.e. "drop point" blade and thumb stud.
The "Sogwinder II" is the knife which closely resembles the Sog Tomcat, again, with the significant difference in the blade style, again the "drop point" blade and thumb stud. The "Sogwinder II" is significantly larger than the "Sogwinder I".
I hope this sheds a bit of light on the Sogwinder knives. However if some should find a genuine Sog "Sidwinder" or "Sidewinder", please feel free to enlighten me because I truly enjoy learning.
Regards,
d-1