Steele Rubber windshield gasket

I'm going to be pulling the windshield in my '75 duster to fix some rust and paint the car in a few weeks. I've been looking around at a few different places, and some say that it needs a lock strip, and others dont mention it at all, like Steele rubber.

I find it odd that they say the rear gasket needs a lock strip, but mention nothing about it for the front. Does anyone know if the gasket comes with a lock strip or if I'd need to order one separately?

The reason i ask is I read somewhere that that year had some sort of 'zipper' thing instead of a lock strip. However the gasket that is in the car now does have a lock strip around 3/4 of the gasket with some odd looking seam at the bottom part.

Any advice or recomendations? I've never dealt with this type of gasket before, but I'm eager to learn!!