It appears the glass and weather strip are still available depending on the year of your truck (not listed in your sig/post). Whether you replace one or both is up to your personal inspection. No real labor/time savings doing both at the same time like on other jobs that drive "while you are there..." syndrome.
Not sure if the appearance of the glass would be slightly different over the years, and if that would bother you.
Since it is easy for me to spend your money, depending on how old your weather strip is, it is nice to grab a new set of OEM seals while it is still available.
Once you settle on your parts numbers, if there is a Toyota dealer near you, check to see it they have a parts website. Often times it is much cheaper than walking up to the parts counter. You might be able to order the glass online and pick it up at the dealer locally for the same price as the other online dealers, then you don't have to worry about shipping the glass.
www.toyotapartsdeal.com
ToyotaPartsDeal.com offers the great deal for genuine Toyota parts 68131-90303 (6813190303) Glass, Back Door for $38.19. All parts are backed by the Toyota's warranty.
www.toyotapartsdeal.com
TOYOTA LAND CRUISER 40 55FJ40LV-KCJA , BACK DOOR PANEL GLASS
www.japan-parts.eu