Is there any gasket between the two half case of the rear end axle ?
Vendors are selling a paper gasket #2504 but I didn't find any in either 1914 or 1927 I opened.
Should I put one or would sealing compound be OK ?
I think most people skip the gasket. I use non-hardening Permatex (#2).
A little Ultra Black will work fine. They do not make the gasket for the early cars and making one up is a difficult job because it is so delicate. I started using Ultra Black and have had great results.
Back in the day, when almost everything you bought, other than food, was raped in brown paper and tied with string we used the string for gaskets. We painted the string with Aviation Permatex and laid it in place. Works great for the rear end and torque tube.
I have rebuilt a number of Model A rear ends. Gaskets are used to set preload on the axle bearings. I did a T rear end that was just a tiny bit tight. I used a second gasket and everything came out great.