In my opinion, reused components should be counted as credit for avoiding the production of new components. I agree with @martintorres that it is hard to know what happens at the end-of-life of a building even if it is designed for adaptation or disassembly. That said, there should be some other way of giving credit for design for adaptation and disassembly but should be reported separately (module D according to EN 15978 standard) or accounted for using other non-LCA methods.
Here are some additional resources (unfortunately some behind a pay-wall, but if interested, reach out to the authors):
Work by National Trust for Historic Preservation:
https://forum.savingplaces.org/viewdocument/the-greenest-building-quantifying
My own paper on adaptive reuse LCA with a case study (there are many other papers on this topic):
https://ascelibrary.org/doi/abs/10.1061/9780784480502.089
Conference paper on evaluating flexibility and adaptability of buildings:
https://ascelibrary.org/doi/abs/10.1061/9780784480502.089
by https://www.learningbuildings.com/