The AFV Club 105mm Howitzer is the M102A1. The M102A1 has not been in the active force for about 8-10 years, sjortly after ODS. It was replaced by the M119A1 105mm howitzer. The M102A1 is still in use with some Army National Guard units and has been deployed with them to OIF as NG units have deployed in support of Stability Operations, not in the initial invasion and immediately following.
For the M119A1, Mouse House of Australia does one in resin, here is the link. Looks good, but again, resin = pricey. I haven't seen it in person, nor heard any reviwes on it.
MH M119A1 Bottom line, AFV Club M102A1 can be used in OIF in an Army NG unit.
Hope that clears it up.