I think there is an app for that.
https://itunes.apple.com/us/app/iap-bushings-tubes-reference/id1062399336?mt=8The answer is no . . Those bushing sets are different.
The Jr. Majestic cap is slightly tapered, whereas the Jr. Emperor cap is not.
There are also slight size differences for both the upper and lower barrel bushings.
There used to be a comprehensive bushing/tube table in the library which covered all manufacturers. . I don't think it is there any longer and in place of it we have 20 or so tables, each table being for a different manufacturer/supplier.
If you want to know the numerical sizes you have to look up the Jr. Majestic in the PSI table and for the Jr. Emperor I would try the Exotic Blanks table (I am not sure who is the manufacturer for the Jr. Emperor but I believe Exotic Blanks sells that kit).
Edit:
Actually, I just found the sizes for both kits in the Exotic Blanks table - they sell both kits it seems.
You need to look in: Library -> References -> Pen Kit Bushings & Tubes 2016 -> Exotic Blanks
I keep a copy of the old "comprehensive" (but somewhat out of date) table on my desktop. If you send me your email address in a PM I can send you a copy of it as an attachment but I can't do that here. I found the numerical sizes of both kits you mentioned in that table.
Curt mentioned there being an App with this data. . I don't have either an iPhone or an iPad so I can't comment on this App.
Let me know if you need any further info or help.
Thanks, Curt.
Can I download that and view the tube/bushing data on my desktop (Win7) ?
Thanks, Curt. . The way I read things, the App works only on iOS8.
I only have a Win7 desktop so I will continue to use the tables in the IAP Library.