Actually there were two CS-1 made. One with a three inch bbl, and one with a four inch bbl both with round butt grips. three inch was for US Customs dog handlers the other for regular officers. This order was completed by S&W but 1/3 of order never shipped due to everyone switching to autos, specificly 5906 for regular officers and 6906 for the dog handlers. The 1/3 that wasn't shipped were sold overseas (West Germany) Picked up there by a custom shop they were bead blasted and lazer marked .357 Security Special. While still retaining the CS-1 mark on the yoke. Germans didn't care for them so they were offered for sale through the Rod&Gun clubs for Soldiers to purchase( I have one in three inch). The remaining stocks of these firearms once replaced by autos were shiped and stored at Ft. Benning, where the US Customs firearm training branch was located. They also stored all confiscated weapons from all the federal agencies. Now why are there not a lot of these to go around? Prior to the Clinton years local, state, and federal agencies were allowed to sell off all turned in and or confiscated firearms to help buy newer weapons without using up all our tax money. Once Slick Willy was on board he blocked that and required all agencies to have their storage of post issue weapons and confiscated firearms destroyed. This along with large stockpiles of resurve US military arms were shipped to Anniston and cut up and melted down. Thankfully congress was able to stop it but not after a lot of damage had been done to or military stores of weapons i.e. M-1 Garands, M-1 Carbines, BAR, 1911A1, Tommies, Victory Colt and S&W revolvers, 1903 Colts. The majority of these were still in unissued condition. Don't believe it! Thats fine, sometimes the truth is stranger than fiction. I was there, and have just recently returned from Iraq where the same policy is underway. Join the NRA, if you are a member then get a friend or co-worker who isn't to join. Its the only way we will keep our rights short of a civil war.
P.S. You have a very good firearm and somewhat rare, enjoy it and never let it go you will regret it!