Unless there have been changes in the last year (quite possible), Glock DOES extend the discount to retired military w/ID card; I bought a nice G17C under the program about this time last year. I just made a request for the new IOP form (Individual Officer Purchase form) recently, in hopes of picking up one of the new Gen 4 Glocks in the next few months. Also, if you don't have a Glock LE dealer nearby, you can order it directly from the factory and have it delivered to any nearby Federally licensed dealer. Again, this is how I bought mine, but it may have changed, so verify before using this method. Be prepared to pay a transfer fee to the dealer when you pick it up, of course. You will need to provide Glock with a copy of the dealer's FFL at the time of order.
I also have a S&W order pending right now; haven't heard anything since I sent it in about three weeks ago, but they tell you right on the form it may take up to 3-4 months for a M&P rifle order. The 40% discount is off the MSRP for each item shown on their website, which is a bit higher than the "street prices" for most of their guns, but don't take this as a complaint, just an observation.
Kudos to these fine manufacturers for supporting the troops, even us old(er) ones.