Is this a speed limit sign?

Recently a driver took out a 45MPH speed limit sign and signpost on U.S. 14, as you drive into Harvard from Woodstock and approach the traffic light at Route 23. I reported it to IDOT and they promptly installed a new sign.

But this is the sign (photo) that IDOT put up. Is this a speed limit sign, or is this a warning sign that the speed limit will drop at some point beyond this sign?

It seems to me that this is a warning sign and that it is legal to continue past it at the previously-posted speed limit of 55MPH. Then you can cross the junction at Route 23 at 55MPH and not have to slow until the 45MPH sign near Sullivan's Market. IDOT will review this sign's placement and decide whether to change it.

Just west of this sign in the ditch is the warning sign for the traffic signal ahead. The 4x4 wooden signpost is broken off near the ground, but the sign appears to be in good condition. It should be back up soon.