A-L,
You'll be lucky to get anything. With respect to ARC - I was not a member of the (BAM) team in OHB's time but during my later tenure, I got the impression that they really enjoyed their time with OHB and held (perhaps the present tense is more appropriate) him in high esteem.
My wife has no wish to part with the overalls and I doubt any original team members would be willing to part with anything that reminds them of the era.
If procuring memorabilia was the object of your contact with ARC, I'm not surprised you received little assistance.