No. The current facts and requirements still need assessment.
Compare the positions directly
Identify changes in duties, terms and qualifications. Do not treat an old support letter as proof of a different present opportunity.
TN still requires citizenship of Canada or Mexico, a qualifying listed profession with its specific credential requirements, prearranged professional employment, and temporary entry. Set the actual duty list beside the profession's stated requirements and identify which document supports each qualification. What matters is whether the duties actually performed still match a listed profession and remain professional in character, and whether the employer and the prearranged position are still as described. Beyond immigration, every state regulates surveying practice on its own terms, and a foreign licence is rarely accepted without an application, sometimes an examination, and often an evaluation of the applicant’s education and experience. The proposed duties must still involve qualifying professional activity; neither the certificate nor the employer’s willingness to call the applicant a chemist settles the entire case. Counsel can say whether the revised description still matches the listing the case relies on, and whether the employer letter needs rewriting before the dates change. The practical discipline is an annual review: read the original letter, compare it with the present job description, check the licence status, and correct any drift while it is still small.