Hrddrvs

I have a 2000 2wd standard cab prerunner 2.7 auto. Should these have double cardan joint driveshaft ? I hear x-cabs do but mine is single cab and I have a double cardan joint. If you have a standard cab prerunner please let me know if yours are double cardan. I got this truck recently and have a bad vibration/humming at 30-55mph. I wonder if double cardan on single cab is normal, I cant seem to get any info on this particular question. Any help is appreciated. Thanks.