These take a plastic crystal that is inserted from the inside of the case with a crystal press. You can find the GS crystal catalog on line. Google "GS crystal catalog" and it should come up. It is a PA type crystal. It should be a number like PA 500, PA 503, PA 505 or close to one of these...
The hour hand is staked (riveted) to the hour wheel. When you remove the movement from the front the hour wheel with the hand will remain in the dial. once the movement is out of the way you can easily slip the hand through the hole.
The dial screws are 1.7/ 35 metric thread. That means the threads are 1.7mm in diameter, 35 threads per cm. The length of the threads is 2.55mm. The head is 2.5mm dia. and .5mm thick.
Hope this helps,
I have never found a reliable source for this size screw. One time I did get a few from Howard Miller but they did not have many. I think they robbed them from an old dial.
I finally just identified the thread size and make them when needed. I don't remember off the top of my head what...
The Frodsham clock was repaired back in 1996 by me. At that time they were fixing it up to have on display in the small lecture room near the front door. It is a wonderful heavy brass movement with astronomical dial in a simple burl walnut case and was a pleasure to bring back to life.
This movement was made New Haven. I have seen it in a case almost identical to the Ithica GF. I beleive you will find it in Tran DuLi's book on the New Haven clock company. Early 1900's is my estimate as well.