Did a search and came up with this thread:

Going crazy looking for front windshield weatherstrip...

But, it did not have a definitive answer & the Service Manual is a bit ambiguous too ... the question is, do you have to remove the windshield to replace the rubber trim (Ford P/N F4ZZ-6303144-BAM) that is around the windshield?

As seen in the pic below, mine has decided to split for some reason and is looking pretty tacky.

 

When I had a chip filled at Safelite Auto Glass, the tech there told me that these mustangs come with the weatherstrip already attached to the window. Thus, new weatherstrip = new glass. If you have good insurance they may cover the cost of a new one.........I know USAA will for me.

 

https://mustangforums.com/forum/4-6l...ear-glass.html

read cliffyk's response. now i realize this is for the bottom of the glass, but may apply to your situation as well. using some rubber cement or a rubber-friendly sealant where the crack is may be a viable solution for the repair work involved.

 

So I think I got the answer I needed ... This youtube vid helped:

Day 5 Mustang Cobra Project Ford SVT new windshield - YouTube

First hint, if you watch closely, is you'll see the new windshield with the rubber molding already attached. So I contacted Safelite and got this response:

So the answer is (for anyone else who searches for this) ... you can purchase & install replacement molding, but'll you'll have to remove the windshield to do so.

 

I am in the same boat with my mustang. Ford said the molding is obsolete, but found it on their website. My windshield is cracked in a couple places, and found a used windshield at an auto salvage yard. It didn't have any molding on it. I asked around, and nobody will touch it since it doesn't come with it. So I'm stuck having to buy the molding, take out my old windshield, and put in the used one after putting the molding ion it. Thank you for your help in figuring this headache out.

 

where can i buy the weather stripping? thanks

 

where can i buy the weather stripping