It can be. Of course, you'd need to cut out the holes for the pickups, and sand those off with 220 to prevent from scratching the guitar, then you'd need to drill pilot holes for the screws to go in, so it doesn't splinter the wood.
Rub across the narrow part of the pickguard with your thumb in both the left and right direction. Go SLOWLY. If a bubble starts, stop rubbing and let it set for five minutes then repeat the application process applying pressure slowly in both directions with your thumb.
you don't need to take the strings off to remove the pickguard from a les paul. there's one screw by the cutaway, and another screw around the edge of the body attached to the piece of metal that holds it in place above the carved top. unscrew those and it'll just come off.
Pickguards fitted to acoustic guitars are usually made from thin (2 mm) sheets of plastic (such as PVC), attached with an adhesive just below the sound hole. The material should not be unduly thick or heavy since this might reduce vibration of the soundboard and alter the tone or volume of the instrument.
For others that may be reading, I'd recommend a hair dryer to heat up the adhesive and slowly peel it off pulling at a 45 degree angle. Pull up slowly and the softened adhesive should just let go- don't rush it. Use either naptha or goo gone to remove the sticky residue on your top, it won't hurt it.
You can remove a strat pickguard without removing the strings IF it is a 21 fret neck. Just loosen the strings, and tape the body on the side you're pulling it out so you don't scratch the finish.
so far should take about 10 mins.
Most guitars don't need pickguards, because most people don't harm their guitar with a pick. Even those with pickguards have them for cosmetic reasons.
Even when made from thin, light plastic, these pickguards cover too much of the top and have an adverse effect on the guitar's tone: Just so you don't think I'm picking on Gibson alone (however much fun that might BE…)
A device applied to the surface of a guitar (or bass, etc.) to protect its finish from scratches that may occur due to picks scraping across the top while playing. Pick guards are usually made from some type of plastic, although metal and other materials are sometimes used.
A pick guard (also referred to as a scratch plate) is laminated plastic used to protect the body of the guitar from being scratched caused by picking. If guitarists have heavy picking they could unintentionally but permanently, damage the wood of the body and the pick guard is used to take the beating.
Gluing a traditional pickguard on there will put on too much mass and make the sound worse for it. However, there are solutions and those are what flamenco players use. There's actually no one here, talking about screwing anything, let alone a pick guard to the top of a classical guitar.
