2L Legendary Potential + Premium Cubes?

Yeah, so, what do you guys think will happen if you(for some reason) cube a 2L equip to Legendary before premium cubing to 3 lines?
Either;
a. Can't pcube, stuck with 2 lines forever
or
b. Can still pcube to add a 3rd line

I ask because Legendary potential'd things could only be cubed with super cubes in KMS, and had stamps for adding lines.
Maybe wanted to cube to decent potential(would go for unique, but if I hit Legendary accidentally while L>the right %stat) with super cubes(says it has a higher chance of +rank) for 1.9k NX, then pcube the items to 3 lines when I could afford it(3.1k for 25% chance isn't too appealing).

Though, I'll just end up not cubing anyway, this thread may help other's if an answer is found.

You can get stamps with the fragments of Master Cubes

Are they an option in GMS's super fragments?
http://www.basilmarket.com/show/screen/2...t_rew.html
^ Seems not to list it. There's no 'Previous' button indicating it could have been mentioned before seeing those options. Silver Stamps are 10 fragments as listed on HighOnMushroom's blog for KMS, meaning they should be listed before 20 and 30 fragment options in GMS.

Are they an option in GMS's super fragments?
http://www.basilmarket.com/show/screen/2...t_rew.html
^ Seems not to list it. There's no 'Previous' button indicating it could have been mentioned before seeing those options. Silver Stamps are 10 fragments as listed on HighOnMushroom's blog for KMS, meaning they should be listed before 20 and 30 fragment options in GMS.

Considering they're in the data they have no reason not to add it.

Well, considering the only way to get to legendary tier is to use a MMC on a unique item, it would probably just make sense to use a premium miracle cube on the unique item BEFORE using MMCs to legendary it...and if you wind up getting 21% of a stat in the process of 3 lining it, might as well save yourself the money and not legendary it at all.