I just picked up a Colt Trooper Mk III. The serial number dates it to 1970, the second year of production. I already had a Trooper Mk III with a higher serial number. It is above the numbers in Proofhouse.com so would be later than 1978. The two guns have different hammers. The later gun has a wider hammer than the earlier gun. The pins on the right side of the frame are flush on the older gun but are not on the newer one. So, there was obviously some minor changes done over the years. The question is did Colt use different hammers over the life of the Trooper Mk III? Or, do I just have a replacement hammer?