Hi, I would not worry too much. There is a thread on GMB discussing Egermann Exbor taking over Exbor after 1993 or 1994. the quality is not hugely different but worth noting at auction, the new acid stamp is different anyway but I think both eras produced some unstamped pieces. The old Exbor pieces with czechoslovakia are slightly more beautifully made in general. The Lipsky vases may have had other factories copying them, especially in single colours historically, but I have not seen any companies today copying them, other than the Egermann-Exbor productions. Jindrich had an issue with an auction house selling new Egermann as old Exbor. Which was obviously not accurate but the vases I have seen made there recently are OK quality and they use some old Hlava and Lipsky designs and own the name Exbor today, so they have a kind of right to prouce these things if they want to, as I understand it. There is an Egermann catalogue on Jindra's site showing some of their remakes. A purist would prefer the old, every time but in my opinion it is not literally a disaster to own an Egemann-Exbor piece. I doubt either of yours are modern pieces, certainly not the stamped one saying Czechoslovakia. This is my understanding of the state of play re. this subject and is just an opinion,
Robert