Nate Nagel wrote:

am looking for a hopefully easy to obtain, not too expensive method of
demonstrating that a receptacle is GFCI protected... long story
short. Am selling house, got offer. Home inspector came through and
wrote up two receptacles as being "ungrounded" despite them actually
having the blue stickers on them that said "GFCI Protected - No
Equipment Ground" (duh) before you ask, it would be fairly difficult
to pull grounds to these boxes, otherwise I'd not be fighting. Also
there are a approximately 5 or 6 other receps throughout the house
that I haven't grounded yet that are in a similar situation, and I
don't want to open that can of worms whereby accepting that the lack
of a ground at these receps is a fault that needs to be corrected
leads to the request to ground *everything.* ....

It sounds like the only issue is what to do in terms of making sure that the
house sale goes through. The inspector just noted that the two receptacles
are "ungrounded". That doesn't necessarily indicate any basis for the buyer
backing out of the deal unless your agreement of sale says otherwise.

But, what I would do is simply replace the two cited outlets with GFCI
receptacles and put the same sticker on each of them ("GFCI Protected - No
Equipment Ground"). That would be easier than trying to prove through some
test that the existing receptacles are already GFCI protected. And, it
would enable the buyers to plug in any appliances etc. that use 3-prong
plugs. All of that would be code compliant, so there would most likely be
no basis for the buyer to try to get out of the deal since there would be no
defect that needs to be corrected. Also, if they later asked to have the
other 5 or 6 two-prong receptacles changed to 3-prong GFCI outlets in the
same manner (with the stickers) I would just do that.