Looks like it's rusted a bit too. The truth is you've got the Side-plate off already and removing the rest of the parts is a 2 minute job or less if you know how. If not, I'd say this is a good time to learn as it is easy enough to do and is really in need of a good cleaning! Watch some good video's on Midway, Brownells, Youtube, etc. or get one of your shooting friend's with experience to show you how. Don't force anything, take you time and think before doing.
IMHO the inside should get a thorough scrubing with a stiff nylon toothbrush and Hoppy's, #9, blown out with an air compressor, lightly oiled and reassembled. IMO just squirting some lubricant in there is not enough in this case and is only a short term "bandaide".
Many are intimidated on disassembly but being that we live in our current anti-gun climate, good Gunsmiths are hard and expensive to find, learning at your own pace is prudent, economical, not that hard and quite satisfying. OK - I do not know you and if you are the type with "two left thumbs" and not good with tools, disregard what I have posted and bring it to a qualified GS if you can find one. It should not be an expensive job and shouldn't take more than 30 - 45 minutes to complete.