Yes, If you are a true believer then the book was written for you.
Contrary to what some may claim, the book of Hebrews was actually written to and for true believers and followers of Jesus Christ. "We" and "us" are used quite often throughout the book. The writer was obviously a believer so by using the words he chose to use he was targeting an audience of believers and no one else.
Here is a really clear example where the writer referred to the readers as "holy brethren": "Wherefore, holy brethren, partakers of the heavenly calling"... Hebrews 3:1 and "Take heed, brethren, lest there be in any of you an evil heart of unbelief, in departing from the living God". Hebrews 3:12 And yes this following passage was specifically written for believers. Notice the writer includes the reader in his company as a fellow believer by the use of "our" and "us" and "ourselves" several times. The intended audience should be very clear. Let us draw near with a true heart in full assurance of faith, having our hearts sprinkled from an evil conscience, and our bodies washed with pure water.  Let us hold fast the profession of our faith without wavering; (for he is faithful that promised;)  And let us consider one another to provoke unto love and to good works:  Not forsaking the assembling of ourselves together, as the manner of some is ; but exhorting one another : and so much the more, as ye see the day approaching. Hebrews 10:22-25 Keeping true to the overall context regarding who the audience was, this following verse was definitely written to believers as already shown in the previous four verses. Notice the use of "we". For if we sin wilfully after that we have received the knowledge of the truth, there remaineth no more sacrifice for sins,  But a certain fearful looking for of judgment and fiery indignation, which shall devour the adversaries. Hebrews 10:26-27 I went through the trouble to explain the obvious because a lot of people purposely takes these and other passages in Hebrews out of context because the original intent does not fit their doctrines, mainly that of "Once Saved Always Saved". The hyperdispensationalist uses the false rescuing device of "this wasn't written to me so it doesn't apply to me". If this is the case then none of the Bible would apply to any of us. The letters to the Romans would be for the Romans, Philippians for the Philippians, Revelation was specifically for seven actual church's, and so on. This pick and choose logic is illogical and really just plain false. It's time we start taking God at His Word and stop believing the lies of men.