dBASE III and indexes

I have an old dBASE III table and its index file. I don't have dBASE III
installed on my machine. I imported it into Access2000, combined the
contents of two fields into one field (ie: the contents of field1 and the
contents of field2 were all put into field1 with a comma separating, and
emptying out field2). Now I want to export it back into dBASE III with all
the fields intact, just one of them is now empty. What will happen to the
old index file? Can I still use it? Access won't create a new .ntx file (or
at least I haven't been able to) and I don't have dBASE III to work with.
But the way I figure it, the table hasn't changed, except for data has
moved. Any suggestions?