A quick learner from Washington says:
September 12, 2016
looking for a replacement part for a milgaurd window. The only number on the window was MG-1-ALI-CBA
Tom from SWISCO responded:
September 14, 2016
It's tough to say. I'm having a hard time making out the finer details of your top sash guide. That said, our 18-008 may be what you want. Carefully compare our dimensions and style to your own measurements to confirm if this can work.