Like Jim said, it sounds like your vendors are using two names for the same thing. FR4 is a flame-resistant glass-epoxy composite material. The "resin" is the epoxy prior to curing, and the "glass" is a matt of fiberglass strands that gives the composite strength.
There are dozens of products out there that are generically sold as "FR-4" by fab shops that want to keep costs down by buying from whichever laminate manufacturer offers the lowest price at a given time. For hobby projects, it's mostly safe to treat these materials as equivalent.
One distinction to be aware of, especially if your design is using lead-free soldering process, is "high-temperature FR-4". This refers to a key property of epoxy called the glass transition temperature. Above a certain temperature, the cured epoxy will undergo a phase change that causes it to change volume (expand or contract) significantly (like 1%-2%, I think), which you don't want to happen.
With lead free solder, a higher processing temperature is needed compared to tin-lead solder, and high-temperature FR-4 should be used with this process.