41 C.F.R. § 102-38.65

You must allow prospective bidders sufficient time to conduct inspections of the personal property to be sold. If physical inspections are prohibited due to agency circumstances, you must notify GSA in writing at least 3 days prior to the start of the screening period. The length of the inspection period depends on whether the inspection is electronic or physical. You should also consider the circumstances of sale; the accessibility of the sales facility; and the volume, type, and location of the property. Normally, you should provide at least 7 calendar days to ensure potential buyers can perform needed inspections.