The Motorola 19CT1 at the ETF Museum also has the "Experimental Not For Resale"" stamped on the top. I believe there is at least one additional, not counting the current e-bay offering, with the stamp. The ETF set has the original 19" tube with the gold painted mask. ETF - Motorola 19CT1
http://www.earlytelevision.org/motorola_19ct1.html
-Steve D.