Are you expecting that the rowID's be consistent based on the physical order within the given file? Unfortunately you would need to set up the ordering mechanism to KEEP them in that order during the initial bulk loading process since the text file is the only thing that has any form of a physical order.

Tables do not have a "natural" or physical order, so just because data was loaded organized in a given way in the text file does not guarantee that the table will retain said order. Additionally, queries are designed to optimize performance and will use whatever fetching mechanism gets them the data in the most expedient way (so you don't always get the data coming back in the same order UNLESS you enforce it with an ORDER BY clause).

That said - depending on how you're intaking the content, there are ways to insert into the initial table in such a way as to establish and ordering key. If you were leveraging SSIS - you might care to look for "row number generation SSIS" in google. or grab some existing built components such as this one:

http://www.sqlis.com/sqlis/post/Row-Number-Transformation.aspx