I agree with Cogar. I don't think it is that old either, which is why I hesitated posting it here. But I figured that if there was a safety test for pottery, someone here would know about it. I think the water testing idea is probably my best bet.
And I do have the 3M lead check kit. I have used it on many of my metals. The only thing that tested positive for lead (in a HUGE way!) was this small pewter pitcher. I was told it was made in the early 1800s (before lead content was regulated in the U.S.) and I can't be certain, but 3M check certainly indicated heavy lead content. The swab turns pink when it touches lead and for this vessel, it went from pink to dark pink to black! And this was on a portion of the vessel that I thoroughly washed and rinsed, so that blackness was not from patina.
There are makers marks on the bottom, but they are so faded as to be nearly illegible.