Hi, I'll answer two questions at once. Polydor GR-2004 is: Harumi Ito/Japanese Oldies - Kage Wo Shitaite. Since you mention Polydor CD-4's, I need 1 more to have them all. Might you have GR-2006 Yoichi Sugawara-Live? If so, I'd offer a generous trade for it to finish my Polydor set.
Next, about the Fausto Papetti CD-4 on red vinyl. I have that one too, plus others from that label, also on red vinyl. Apparantly Kuopin had a deal to release Japanese CD-4's in their market. Some others they did are from the Philips Japan CD-4 release list. They actually aren't too bad, not like some of the Taiwan/Singapore/Hong Kong CD-4's I've tried. Those actually had so little carrier that the CD4-50 couldn't stay locked, they just shattered and sputtered totally. The red vinyl ones on Kuopin sound rather like a worn USA pressing, with some noise, etc, but playable and definately CD-4. On another label, I can't recall right now from work, it boldly said CD-4 on the jackets and OBI's, but the LPs actually are stereo (or mono), no carrier at all! I'll post the name of that label later from home, started with a J as I recall. I tried about 20 of them, all had no carrier but were sold as CD-4's. Avoid those obviously. Anyway, to finish on the Fausto red vinyl, it's JVC original Japanese release number is CD4W-7099 for the genuine quality pressing of that LP.