No. Re-post / start a new thread. Many times the old-threads will be cross-linked (I see this pattern a lot on HN)

Can we post one referencing previous HN link? ?

I've not seen it done but, what's a good one? Putnam award?

I wanted to add that some zombie/necro posts are useful outside the context of HN.

For example on retro computing boards it makes me so happy when someone bumps a 5 year old thread to share new details, benchmarks, etc. about some card or motherboard where the ancient thread is first thing that appears in search results.