I am wondering what the size of the rivets that holds the Cowl Lacing to the Cowl? Someone has used some blue push in plastic things t hold it on now and I am wondering if they drilled out the holes or if the just pushed them in. I have not had a chance to measure the holes yet but I would guess they are about .150-.200. Not sure why they would use those on a model T but who knows. I am hoping that they have not been enlarged.
The lower photo looks correct to me. The lacing is held with split rivets. The head under the cowl area above the gas tank on the Improved Open cars.
The split goes into the fabric lacing, like doing a band re-lining.
Lang's sells split rivet kits for this, brass, black or nickel plated, p/n4060n for the shiny nickel on the Improved Cars
They are 3/32 diameter, and 1/4" long, black split.
Don Lang buys them from me, 1000 at a time! On the 1925 and earlier firewalls the head goes in from the top. They are also used to hold the patent plate on the firewall.