First I would advise you to have information on pumps before you go out buying one. As for pictures, all 300s look alike.
I believe you have one-half of a Tokheim 300 Twin. I cannot find anything to tell me what the "X" means, but if you had a copy of my Gas Pump ID book you would notice the P means that the door or doors have ad glass panels.
Sight glasses were governed by the laws of the city, county, state you were in. Some of the above required them, but then in the 50's they started to dissappear. If they broke, the repairman would simply put a pice of sheet metal over the opening and shut if off.
Faces were all the same, you should have no problem finding a pair, the computer is probably the correct one. Just get Joe to rebuild it for you.
If you are looking for information about your pump just go to Ebay, type in 'GAS PUMP LITERATURE A88"
For pictures of your pump and my Gas Pump ID book see my website (the largest website devoted to the petro hobby, over 10,000 images) see:
www.petrocollect.comJack Sim