Rebuilders sometimes mix and match the injectors - if they are rebuilt then the stamp on it means almost nothing. You'll need to verify the pop pressure before you put them in. I read this in a thread here a couple months ago when someone got a "mixed bag" of rebuilt injectors. They were all pop tested to proper pressure but had different stamps.

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TC
Current stable:
- 2004 Mazda RALLYWANKEL
- 2007 Saturn sky redline
- 2004 Explorer...under surgery.

Past: 135i, GTI, 300E, 300SD, 300SD, Stealth