This is a standard issue IM field jacket. I think a warehouse was found full of these because this past year I have seen many, but before this none. These were made/worn in the early 1980s. The material was not very good so the camouflage faded quickly and the jacket became very shiny. Yours is about middle quality. I have one that is much better and another that is much worse
IM was the first to switch to US based Woodland. The ET (Army) adopted Woodland camouflage soon after and they also had a problem with the cloth. This was fixed around 1986, if I remember correctly.