No. They got sloppy with at least one big position with suspicious timing. [0]

[0] see infamous tweet about position 24h prior to announcement.

If he used different wallets to buy different coins then the correlation might not have been noticed. Buying coins right before they're listed on Coinbase is still suspicious but it would have been less suspicious at least.

There are so many other ways to do this that are infinitely harder to track. Suppose token X is going to hockey stick. You can short a derivative that shorts X. You can long a derivative that longs X. You can leverage a lending protocol that contains X. Etc.

"Buying X when X will go up" has got the be the most unsophisticated way possible one can leverage insider information. Not to mention a basically guaranteed way to get caught.