Do LED lamps qualify automatically for this credit, regardless of its rated lifetime?
Correct.
The MRc4.1 form is linked to the data in the MRp2 form. The MRp2 form requires a list of the fluorescent lamps and high pressure sodium lamps. No data is requested for the LED lamps.
The only requirement pertaining to LED lamps is for all illuminated exit signs to use either LED or LEC lamps of 5 watts or less.