For those who have SBS or are planning a Form 1:
AimSurplus has LE trade in 14.5 Rifle sight barrels for Remington 870s for $129.
Based on the photos these appear to be similar to the DEA barrels with the XS express sights rather than the traditional Remington Rifle sights.
The caption says they are 3 inch chambers but the item description says they are mixed 3 inch and 2 3/4 inch. There was not an option to specify.
https://www.aimsurplus.com/products/...w-rifle-sights