All the license files I've ever received will work with previous versions (certain exceptions when the FlexLM changed versions). So I think you could use those licenses with WF3 or WF2. Note that a floating license is keyed to a server NIC so you can only install it on the machine it was created for. Since they are floating licenses anyone who can connect to that server can run them.
Since it sounds like these were some kind of demo license, maybe there is something unique about them that prevents them working for older versions.
In Reply to Robert Altman:
I have 30 SolidWorks users and a few of them want to learn ProE, problem is I only have 8 active seats of ProE which are all being used on a daily basics.
I also have 10 inactive seats identified as release " WF 4.0 PreProd Flt Lic" which would be sufficient for training purposes.
What build code is the preproduction version of WF 4.0, I thought it was F000 but tech-support is telling me it would be C000
I'm between a rock and a hard place, if C000 is the only preproduction version would anyone have it and be able to put it on an FTP site?