I opened up a new (to me reel) curado 50 e to clean out the bearings and found "SMR 103 A5 LD" inscribed on them I don't know what kind of bearings these are and they aren't factory since all the others are blank. Anyone have an idea?

I believe Shimano has multiple sources for their bearings, or perhaps their source gets them from multiple manufacturers. I've had some that were blank, some that had inscriptions, some had removeable shields, some didn't.

Tom,

It's an ABEC5, bet it is in the spool support line, behind the engagement pin maybe...

 

Shimano does install 3' & 5's in some reels, depends on the series.

 

Tight Lines! 

It's  a Boca 3x10x4 ABEC5 Lube Dry. LD is the way they come, not the way they should be run by the way. ZZ are Stainless, Y-ZZ are Ceramic Hybrid

Thanks guys