The Colt "E" frame was the older models like the Official Police and Officer's Models. The Mark III is the totally different "J" frame.
NO parts interchange.
In addition, the "E" frame used the Old Style ejector design in which the ejector rod is a more complicated design that can't be disassembled without two special tools.
Some people have older Colt parts manuals that show the parts and Colt factory parts numbers.
Coltparts shows most factory parts numbers, but they don't show all the variations.
Colt Official Police Double Action Revoler
Here's the part number for an "E" frame ejector rod: 50347R. Some sources show it minus the "R" as just 50347.
NOTE: The part numbers shown on the Gun Parts Corp site are NOT factory part numbers.
Some sources of Colt "E" frame ejector rods:
Jack First possibly.
Poppert's list them:
http://www.poppertsgunparts.com/cgi-bin/webdata/webdata_gunparts.cgi
Here's the tools necessary to disassemble and reassemble the Old Style Colt ejector system. Without the tube wrench you cannot get the assembly apart.
Ejector wrench:
COLT WRENCH | Brownells
Ejector rod bushing tube wrench. This is a MUST have:
COLT CRANE BUSHING TOOL | Brownells