ICS is still producing airsoft, but they regularly redesign their guns much like TM and other companies are doing. You should be able to find somewhere, but it'll just take a lot of searching. Have you tried
www.evike.com?
They have shitty customer service and sometimes mess up your order, but they often have odds and ends that other places might not carry.
Good luck man and check to see if there is another part out there that you might be able to substitute in if you can't locate the actual ICS made part.