From what I have read about it, for just about all of of the VJ recordings, The Four Seasons partnership has possession of the Stereo Album master tapes. Most (not all) of the mono singles masters and the multi track tapes were left at Bell Sound and never picked up by VJ and are likely lost forever. As part of the court settlement with VJ over unpaid royalties, the partnership has the rights to all that VJ material. For the Phillips years, the partnership has in their possession, the 8 track multitrack for DAWN, but I am not sure what else. On just about every CD that has mono versions of the Seasons hits, they are fold downs from the stereo album masters, but a few of the mono tapes do exist (like Ronnie). For the 45 releases, Bob Crewe created mono 45 cutting masters that had extra processing and compression, to make those records literally jump out of the AM transistor radio speakers. Since it appears those cutting masters are gone, the only REAL way to make a Four Seasons Hits Collection that sounds like their 45s did in the '60s is to get all the hits on first press, Mint 45s, and master it from THOSE. Thats the sound of the Four Seasons, the sound of the East Coast. And I 100% agree about that first press of 'C'mon Marianne". It IS amazing!! I had one and it always jumped out of my speakers. Even today, I remember how great that 45 sounded.