A more literal translation of the Greek would be if we ourselves are found to be sinners.
1 The suggestion seems to be that by rejecting Mosaic law as a means of justification, one occupies the same status as Gentiles before God, so called sinners.
2 Sharing the status of Gentiles (those without the law) is not however equivalent to transgression of the law.3 Christ is not an agent of sin.4
17 But if, in our endeavor to be justified in Christ, we too were found to be sinners, is Christ then a servant of sin? Certainly not!