You are confused
Older road frames designed for 5 or 6 speed freewheels were often 124mm-spaced, road frames designed for 6-speed freewheels or 7-speed cassettes were 126mm-spaced.

Modern mtb spacing is 135mm (with 8 and 9-speed freehubs; 7-speed mtb wheels were sometimes 130mm, sometimes 135) and modern road-hub spacing (with 8, 9 and 10-speed freehubs) is 130mm-spacing. 7-speed road freehubs were usually 126mm spacing (though sometimes they are 130mm because 7-speed groups were still being produced after the advent of 8-speed, and some 7-speed hubs were put on 130mm-spaced frames, so that's the few 7-speed freehubs that were 130mm-spaced).