I have one of these in my 58. Somehow antique auto battery has managed to figure a way to put the new gell battery inside the old style cases. Most are famaliar with the optima line of batteries that essentially have 6 round cells. These are what they put inside your case. They never need fluid but do need to be kept charged.
The battery caps are dummies that open into the inner part of the outter case. By putting liquid into the case you short circuit the battery. A No No.
Did you not want a maint free battery when you purchased it??
If not the acid filled ones sell for about $100 less. I had one and it went bad for many reasons.
I have switched all my cars to optima/gel batteries. I got tired of cleaning up the acid splatter ect all the time causing corrosion.
Sun Prairie, Wi.