I could be wrong, because I am not the market, but I believe it to be the former.
To get an answer to this, I think an update in TSLA's largest institutional holders will be more telling than the Q4'19 earnings. If it shows that there are a few big funds that accumulated very large TSLA positions during Q4 at prices in the high 300s, and 400s, I'd argue that these are more likely long term investments based on Tesla's improved fundamentals and Giga Shanghai + MY ramps, than speculative plays on strong Q4 earnings.
A lot of swing traders and hyped up longs have definitely jumped on board too, and these may take profits or just jump ship if Q4'19 disappoints or is just good. But I believe there must also be funds that are still on the fence about heavily investing in TSLA, because H1 2019 is still fresh in their memory, they believe Q3'19 could've been a fluke, and there were some one-time tailwinds (FSD deferred revenue, $85M in other income) in Q3'19.
My belief is that if Q4'19 (and Q1'20 / Q2'20) results are just good but no more than that, smart institutional investors will continue to jump on board. Q3'19 really was that good of a quarter in terms of cost reductions and margin improvements (in my opinion TSLA's best quarter ever). It's put Tesla on track to be a very profitable company, and even more so after Giga Shanghai and MY ramps. As long as they don't disappoint and miss targets, I think SP should continue to go up.
Personally, I'm expecting Tesla to beat expectations in 2020, potentially by quite a big margin. If things go really well, I think they could deliver as many as 650k vehicles, book $4B+ in EBIT, and have $20+ Non-GAAP EPS. If that happens, maybe we could see a SP of $1,500-$2,000 in 12 months.
None of this is advice, just my opinion on things, which could turn out to be wrong.