It will benefit greatly from a little TLC. That being Springs, Shims, and some careful polishing/smoothing.
To start I would get some wide Craft Popsickle Sticks, Adheasive, and some Fine sand paper for Automotive body work. You can get it down to something like 2000. I use 400, 800, and 1000. I cut the sand paper into pieces the width of the popsickle stick, and 3 inches long. Glue on the end of the stick, and let dry. Mark the stick with a Majic Marker.
Down Load and Print off the 2 following Articles:
http://www.sp101trigger.com/index.html
http://gunner777.wordpress.com/2008/08/24/ruger-gp100sp101book-of-knowledge/
Read both of the above Guides a couple times.
You will need the Wolff Springs (Revolvers Shooters PAK Ruger GP100 Series.
And Shims.
http://www.triggershims.com/ruger_double_action.html
You can get Springs and Shims from TriggerShimsDOT Com.
I normally use .005 Hammer Shims, .003 Trigger Shims, and .002 and .005 Hammer Dog Shims.
I have the following Drill Bits with Hex Head to clean up the holes
BY HAND. 5/64, 3/32, 13/64, aned 1/4.
I also have a 1/16 Punch, and Feeler Gages.
You will also need a Flat File to work over the Hammer Spring Strut before polishing on a Buffing Wheel.
And I would order some Wood Handle Q Tips from Midway or Brownells. I use them in a Drimmel Tool with polishing compound to slick up the Latch Spring/Trigger Return Spring Hole.
The Latch Plunger Tool sold by a member on this forum is pretty handy also.
Get some tools, and read the above posts, and you can have a very slick GP100 or SP101.
Bob R