Those three numbers are found on your broadcast sheet and aid the line person to select the proper one for your car. Variations include A and B bodies, standard or Hemi. My numbers were yellow and had to make my own stamp.
Random thoughts. The IVR in the gas gauge may be behaving inconsistently. Have you confirmed that the gauge cluster is grounded to the body? You may have two problems, fuel sending unit (chinesium) and temp sender ( taped threads?) I tend to think that your new fuel sender is bad because you can...
The square foam blocks are slit partway through in the lengthwise direction and placed on the top/inner edge of the inner lens. That way when the outer lens is installed, the inner lens is held in place under tension.
Tire well is made to hold original size tire only. A original size but wider does raise the cover and causes a bump in the trunk floor. Look up the diameter of the original tire and compare to the diameter of the proposed tire.
No tool needed if concerned about boot damage. Backoff nut 1/2". Insert pry bar in a way to exert separation pressure and smack spindle. It will separate.
New gaskets, new heater core, clean and refurbish. Does this include R&R time? New heater hoses, clamps. Are all the parts on site, or do you have to order? You're talking to an old mechanic who used to work "flat rate". How long does it take?