Used to be pretty big into the airsoft scene, so i'll throw in some input.
FALs that are reasonably functional are few and far between. They aren't designed in a way that you can safely disassemble them without breaking the air nozzle in the gearbox or the hopup housing (chamber). Just needs to be a very slow and cautious process.
The ARES brand FAL's are probably the worst for function and disassembly. They are also not 1:1 scale and are slightly undersized. Perfect for a wallhanger if you don't mind the very slight issues of scale. However, the finish on these are pretty nice compared to the rest.
King Arms is another manufacturer which is full scale I believe, and are a bit more desirable to active players than the former. However, they all have the plastic furniture, adding a wooden grip or stock will be either a ton of work or near impossible due to the design of the gearbox being housed within the pistol grip itself. However, there may be wood kits available online to remedy this. Just expect any wood grips for these kind of things to be very thick dimensionally and fragile since its wrapping around the motor cage portion of the gearbox..
ASG(or JG, same folks) also produce a FAL, and will be significantly cheaper compared to KA/ARES. However, quality of build will reflect pretty strongly to the price.