Just ordered a set of night sights for my 1990 Deer Magnum that I have configured for HD (20" remchoke barrel w/ rifle sights). If anyone else is thinking about this particular upgrade, there are two versions of this sight. One set is for 2009 and earlier 870s (#34660) and the other is for 2010 and later (#34662). Note, this is the barrel's manufacture date and not the receiver if you have a mixmaster gun.
I ordered mine (34660) from Amazon for $46.60 total w/ free shipping. Quite a bit cheaper than the 34662 from Amazon or OP, and way cheaper than the 34662 direct from Remington.