Hey there! I recently did a resto project on a 60's acoustic guitar, and ran into a similar problem. My tuners were extremely dry, and didn't hold a tune very well. They also had two bent posts, which made me decide to purchase new ones. Unfortunately the tuners I had were smaller than todays popular size, so I was forced to use the originals or drill holes. Before I started drilling, I decided to see if I could fix up the old ones. I found this great site with a tutorial on reviving vintage mandolin tuners
http://www.lutherie.net/tuner.maintenance.html which are luckily similar to the ones on my guitar. I followed the steps and now the tuners work perfectly, and I only had to spend about $7 on lubricant that I can use on other projects as opposed to the cost of new tuners. I'm not very familiar with your brand of guitar, but I would definitely recommend trying to fix up the tuners before drilling holes for new ones, it's definitely worth it.