I did a little research a few months ago and the conclusion I came to is that no, it is not. There is a forest service shooting restriction that covers all of Harris Park.

Now it's a bit odd because the notice is from 2009 and indicates a 5 year closure but I have shot at HP since then and it was not signed or closed. I think last time I was there was in 2011. I have been back a few times since but it was either gated shut or marked "closed to shooting." Last time I was there was about a year ago and the sign indicated a recent closing due to fire danger (this was right after the Black Forest fire.)

Best bet would be to call the RD office.