My institution is working on a big map project right now. We use museum accession numbers to identify them, which do not include the date of the object but do include the date of accession. For maps that we have no provenance for, we used a new accession number and just numbered them sequentially. All of the maps have labels that have the accession number and date, if known. I agree with Elizabeth Rose that it’s probably easier to just assign them numbers and use Excel or something else to capture all of the details.
As far as storage goes, we have a number of maps that were humidified and flattened, which is something that is actually pretty easy to do without a ton of equipment, although some caution does need to be taken if the paper is fragile or the inks will bleed. Otherwise, we have many rolled maps that have been rolled up for years and will likely stay that way unless we get money to have them conserved.