Well, believe me or not, it's no skin off my nose but that plug is not a drain plug. Check the subject here on the forum to read the sad stories of those who were told, or decided, it was a drain plug.
There is perhaps 3/8 inch thick crumbly cast aluminum crankcase with the flywheels right there around the plug.
No one, and I mean no one, should ever remove this plug..........pg

 

Heh, heh, when I was a pup and had my '72 CH I did my first oil change. yep, removed that plug and couldn't figure out why only a wee bit of oil drained. I learned 2 things - the oil is s'posed to be in the oil tank, and that ain't a drain plug. Fast forward several years and I'm overseas while my Dad has the bike at a friend's shop, Duck's Putter Parts. Duck went through everything. Normal procedure was to pull that plug and do what HD should've done - weld it up! Had 14 cracks in the cases, plus he replaced the lower right rear corner of the tranny as preventive medicine. The motor was being bumped to 77" and was going to be hammered, especially stoplight-to-stoplight on Saturday nights. The motor and tranny held up, though the excess power regularly cracked welds in the Corbin Gentry frame.

It gets pointed out time after time - get thee a factory manual. Pull the top end off and inspect everything. At least you'll know what you've got.

 

.sometimes bikes change from one year to another...sometimes bikes have different problems than another bike..personally i am the guy that would probably try and start it.....cause i couldnt help myself.but i would recomend not to.you might as well take the heads off and take a peek.see what you got.if all is good you can put it back together with no worries.it just cost me 630 for pistons and a bore job plus valves/guides etc if youve rebuilt auto engines you should have no problem working on an ironhead......i had no experience with ironheads 6 months ago....now i have learned alot...mostly the hard way...story of my life..
if you want the bike get it.if not now when?you gonna wait til maybe he drops the price a hundred bucks??if you do 10 years will go by before you actually get one.....life goes like that.---good luck

edit---if you dont want it let us know where its at.might be close to someone.

 

Here's the thing....most of these old ironheads aren't worth the $ you need to put into them to restore them, even after its been restored. However, what you need to think about is how much $$ is the equivalent of that feeling you get when you're riding. that factor x really does matter. I paid 3500 for my 83 and I think it was a steal, even after I rebuild the engine this winter.