The example of the Bereans incident is not given as an example for us to follow. It's not stated "This is the example to follow".
It would however be natural for Jews to check their own scriptures. It would be less likely that Paul going to preach to Gentiles would be teaching them from OT scriptures because they'd have less meaning to Gentiles.
And here's another thing too. Paul was teaching a 'new gospel'. It was not found in the OT. It certainly didn't contradict the OT, but what Paul was teaching was new. Else we'd be banned from eating pork, we'd be worshiping on a Saturday, and we'd all have to be circumcised.
Furthermore in Acts 15 when we see the Apostles making a decision on what to do they listened to Paul, they listened to Peter and James ruled based on what Peter and Paul said, as well as scripture.
The incident of the Bereans is simply given that that's what they did. Others rejected the message - such as the Thessalonian Jews (initially). We're just shown these two things. Neither incident says "Do this...".
"The Bereans, on the other hand, were not adherents of sola scriptura, for they were willing to accept Paul’s new oral teaching as the word of God (as Paul claimed his oral teaching was; see 1 Thess. 2:13). The Bereans, before accepting the oral word of God from Paul, a tradition as even Paul himself refers to it (see 2 Thess. 2:15), examined the Scriptures to see if these things were so. They were noble-minded precisely because they "received the word with all eagerness." Were the Bereans commended primarily for searching the Scriptures? No. Their open-minded willingness to listen was the primary reason they are referred to as noble-minded—not that they searched the Scriptures. A perusal of grammars and commentaries makes it clear that they were "noble-minded" not for studying Scripture, but for treating Paul more civilly than did the Thessalonians—with an open mind and generous courtesy (see I. Howard Marshall, "The Acts of the Apostles" in the Tyndale New Testament Commentaries [Grand Rapids, Michigan: Eerdmans, 1981], 5:280)."
WHY THE BEREANS REJECTED <I>SOLA SCRIPTURA</I> (This Rock: March 1997)