For some no problems, for others lots of problems.
About $130
No published sn data
Find a gunshop and ask for help
25-80 USD depending on specifics
try: gunparts.com gunsnparts.com gun-parts.com
One drop on each slide rail.
$25-$65, depending on condition. These are not high dollar guns.
No published sn data.
If you don't have an owner's manual, find a gunsmith and ask for help
No published sn data.
Each one has its own quirks. Some run, some don't.
Impossible to answer without a DETAILED DESCRIPTION OF ALL MARKINGS>