Funny. Another referred me to Brownells as well. Unfortunately, they also don't have any in stock. I added myself to their notification list though, so if/when the part comes in, I should receive an email.
Yup, that's the part. #301-000-060 for $34.29. I too was surprised at the cost, but what am I going to do?
I lost the part cleaning the gun -- somehow. I can only guess it came loose in my gun case, and the part fell out while opening the case in the field. Who knows?