The 90-230mm f/4.5 was made by lens maker Tokina in several different iterations and sold under numerous brand names. As far as I know, the 90-230 was available in Sears' catalog from 1968 to 1979 and was offered in M42 mount only (along with the Mamiya SX variation of M42) until the Close Focus version was introduced in 1978. The Close Focus was available in the major mounts of the day.
Some years (?) after the 90-230mm was introduced, Tokina began making a 75-260mm f/4.5 zoom. As with the 90-230, the 75-260 went through different iterations and was sold under many brand names. But it wasn't sold as a Sears until 1979.
More info here:
Vivitar (Tokina) 75-260/4.5 - ALMOST the biggest T4
It seems production of the 90-230 and 75-260 overlapped for several years in the 1970s, but I believe they were distinct lenses with different designs. Yet in the late 1970s, both lenses were redesigned and assumed a common form. They became smaller, shed their tripod collars and gained a close focus setting.
In their Fall/Winter 1979 catalog, Sears replaced the 90-230mm Close Focus with a 75-260mm Close Focus. But Sears literature shows that the Close Focus versions of the 90-230 and 75-260 seem to have the same optical layout and specs - apart from the zoom range.
And as advertised, my copy of the Sears 75-260 Close Focus does in fact have a wider zoom range than my 90-230 Close Focus. But other than the zoom rings, they look like twins.
I haven't yet used my 75-260 very much, but P.F. member Sagitta has a copy of the 75-260 and has posted many photos from it in this thread.