That is a common tactic and you have already spotted it, which puts you ahead of most people. A complete quote covers the site measurement, fabrication, hardware with the brand named, delivery, installation and the removal of whatever is there now. Anything missing from that list will appear later. Ask for the warranty split between glass and hardware as well, because they are usually different lengths. Shower Doors Prices
https://showerdoorprices.com/ quoted ours with everything in one figure and the estimate visit itself was free. Get the hardware finish written down too, substitutions there are the most common surprise on installation day.