I have both a Government Pocketlite model and a stainless Mustang. Both of mine are fine, reliable, and suitably accurate weapons. Being locked breach pistols, it seems to me that they have less sharp recoil than similarly sized blow-back .380's I have fired like the Walther PPK/s (very similar in size to the Government model), they are fun to shoot.
Now to answer the original posters questions ("..I would like to know the difference between the Colt .380 Gov't and the Colt Mustang Pocketlite. I know that the Gov't has a barrel bushing and grip safety where the Pocketlite doesn't, but are those the only differences?"):
The Government model is larger, having both a longer barrel and a longer grip than the Mustang. Much like the difference between a full size 1911 and an officers model...but on a much smaller scale. They also made a Mustang Plus II which was the short Mustang barrel and slide on the longer gripped Government model frame.
The Government and Mustang models were available in either all steel or Pocketlite versions, the Pocketlites had a steel slide with an aluminum frame. I don't believe the Mustang Plus II was available in a Pocketlite version. The all steel versions were available in blued, stainless, or with a nickel finish. Some two tone versions were also available.
The Pocketlite guns had what I believe was called a ColtGuard finish on the aluminum frames. Both the frame and the slide on my Government Pocketlite are black. Pocketlite guns with stainless slides came with a gray finish on the frames.
The Government model used a barrel bushing and a short guide rod. The Mustangs had no barrel bushing and used a full length guide rod. The guide rods and triggers on all models were plastic (nylon I believe).
The only other plastic parts were the grips. I've replaced the trigger and guide rod with stainless versions on my Mustang, and the grips with black micarta. My government model is still using the plastic parts, except for the grips which are now ivory.
None of these Colts had a grip safety.