Thanks for the info. The one I have was converted in '35. I think the latest conversion stamp I've seen is '49. I don't look at these often, but figured I'd pop the question since I don't see much of anything about these rifles.
If anyone is interested, here's a quote from this forum post at http://www.thehighroad.org/showthread.php?t=306041
"In the late 1950's and early 1960's the Indian government converted fairly large numbers of RFI No.1 Mk.III SMLEs into single-shot smoothbore 'muskets' for use by urban police and prison guards".
And another with some info. Seems that these old thing are still in use. Scroll about 1/3 down the page to Section III – Arms and Ammunition http://www.mppolice.gov.in/static/PoliceRegulationsNew/twentyfive.htm
NOTE: this URL isn't working from here for some reason. I've tried 3 times to redo it with no luck. Maybe the URL is too long to show up on here and work from the post. If anyone is interested, send me a PM I can try to send it to you that way.