very common, its easier (and less common) to do the following "fix" to your tailgate:

this doesnt allow you to just pull the tailgate off, you gotta undo something first, which is something thieves arent usually going to stick around for, or willing to mess with. also dont forget you need to ENGRAVE your new tailgate with your vin and/or name somewhere inconspicuous. i have a feeling that if you look on craigslist you'll find your tailgate. a buddy of mine recently had his stolen, recovered, and the guy arrested because he had this info on the tailgate. went to go pick it up with a friendly call from craigslist, and an hour later had him arrested.
if anything EVERYONE needs to go scratch their name into their tailgate right now. tailgates are NOT cheap. you're looking at least $600-1000 for replacement.