So is there a reason why you're R&Ring the head without consulting the service manual? Do you even know the bolt tightening pattern or the torque sequence? If you're winging it, you'll be back sooner rather than later, probably with a warped or cracked head. Everything you could ever need or want to know about the bolt reuse and acceptable stretch limit is part of the head R&R writeup in the FSM.

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Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]