Front Shock Identification Question
 

If my front struts were changed from Boge to Bilstein HDs at some point, would I be able to tell just by looking at them?

I only ask because I've always assumed I had OEM Boge at all four corners. Well I apparently have had a really slow oil leak that has lightly caked the rear shock which, after a bit of grime removal, indicates someone switched over to Bilsteins.

https://i.imgur.com/gIEAF5Q.jpg

I feel stupid for not finding this sooner.