I had one of these sights but traded it (back) to a Stevens collector in Fla. He said, IIRC, that it was a model 144 and came that way from the Lyman factory; I got the impression that this model was apparently made only for Stevens rifles. Now, if you could only find a nice Lyman Range Control vertical staff (it's click-adjustable), you could have a complete albeit 'put-together' model 103. My own 144 vertical staff appeared to be identical to a standard 2A staff, that is, not click-adjustable but with the usual Lyman dimensions and threads and taking the std Lyman screw-in 2A aperture.
HTH, Joe