The Bird Nest http://www.tbirdparts.com
has complete sets of Interior Screw Kits for each year and model (convertible or hardtop) of Tbirds from 1958-1966. They can be found on Page 40 of their catalog. These sets are separated and identified for easy installation. I have used the 1959 Hardtop set for Rose and they are exact matches to the original ones.
In addition to these sets you can also find a variety of hardware and fasteners on these two websites.
Although they do not have OEM parts specifically for our Tbirds, they do have a lot of parts that can be used on them.