Iver Johnson Model Date

Question
I have an old Iver Johnson revolver which was given to my Dad many years ago by an old friend in Hot Springs, AR who said it was given to him by Al Capone.  I don't necessarily believe that, but the old man did have several pictures of him playing golf with Capone at Hot Springs Country Club (the Club has several displayed pictures of Capone and other celebrities playing golf there over the years).  Chrome plated but corroded from heavy use - end of barrel and around cylinder/barrel joint, and above the grip on the right side where the thumb of a right hander would rest.
5 shot .38 S&W top-break Safety Automatic; 3" barrel; hammer;
double post barrel latch; single leaf hammer spring; bakelite-like black grips; SN M7059 (on left frame under grip; 7059 stamped on bottom of trigger guard); top of barrel reads - Iver Johnson Arms & Cycle Works, Fitchburg, Mass. USA;  Bottom of grip reads - Pat'd Apr. 6, 86. Feb. 15, 87. May 10, 87. Mar. 13, 88. Pat's Pending.  
The patent dates and the single leaf hammer spring seem to indicate that this is a "2nd Edition."  But I can't find any reference to the "M" serial number prefix.  Help!
Can you tell me when this pistol was manufactured and if it was made for black powder (which I suspect) or smokeless.
Thank you.
Doug Nielsen

Answer
Never seen this gun and don't know  much is what a google gave me.  Some time M means model so if you check it drop the m and see if you get hits.  try these links

http://www.american-firearms.com/american-firearms/z-html/company-I/Iver%20Johns

http://en.wikipedia.org/wiki/Iver_Johnson

http://thefiringline.com/forums/showthread.php?t=388288

http://www.thefirearmsforum.com/showthread.php?t=45900

http://www.antiqueguns.com/phorum/read.php?6,17172,17172