Querying legacy table with CQL?

I have a Cassandra 1.x table that looks like this:

CREATE TABLE super_old_table (
    key blob,
    "SomeID" text,
    "Date" text,
    "Priority" text,
    PRIMARY KEY (key)

It has since been migrated to Cassandra 3.x and I'd like to query it using CQL. The problem is that there are Thrift inserts being done with more columns than the definition, so:

1) SELECT * only returns values for the rows in the definition

2) trying to SELECT extraColumn throws this error: "Undefined name extraColumn in selection clause"

What can I do? should I use ALTER TABLE to add the column, are there any risks? there are no caveats listed here: https://docs.datastax.com/en/cql/3.3/cql/cql_reference/cqlAlterTable.html