Yes, the GDO gets a response vis-a-vis status of the iris.
I don't believe this is ever stated or explained in as many words, but on more than one occasion we see SG personnel (usually under fire, naturally, as just about anything else would be too boring) punching in their codes, staring at their GDO transmitters, and then shouting something to the effect of, "They're not opening the iris!" Stargate Wiki confirms this, saying of Iris Deactivation Codes:
IDCs are transmitted using Garage Door Openers, a wrist-mounted transmitter with a keypad to enter the relevant code. The signal is received by a computer which identifies its origin, and an "All Clear" signal is transmitted back once the iris is open; otherwise, the GDO returns a "Do Not Proceed" message.
Common sense says this is a necessity born of the imminent risk of sure death if the iris isn't open when one steps through, and the fact that opening the iris is a manual operation done by whomever is sitting in the SGC control room at the moment -- the SG teams have no way of knowing if the guy on the other end is waiting for them, or if he had to run off to the bathroom!
That being said, on multiple occasions SG personnel at all levels seem to be confused by the functioning of this simple device, sometimes treating it as a "fire-and-forget" (or, perhaps more aptly, "fire-and-pray-they-open-the-iris-before-I-atomize-myself-against-it"! see "Children of the Gods" during the team's eleventh-hour escape from Chulac), other times extending it with never-before-mentioned features (like a "hold" signal seen in "Zero Hour" and then never mentioned again); the above, however, does seem to be its "default" method of operation when the plot doesn't require the added tension.