Fred,
From the brochure, the COMVAC 1300 is pictured with the pre-1973 style toe-touch height adjuster control (part #131669, with ratchet lock #133069), since the part of the control (from brochure) that lowers the mechanism looks the same as it had for the Classic 1CR series and back, whereas yours has the version used since the Classic Omega 1CB (part #131673, with ratchet lock #133073).
~Ben
