Welcome to the forum. You are asked for an opinion, and I have that. I'm not the expert which there are many on this forum, but I do have some observations I've seen over the years.
The first question is how much you like the rug? A person can get cared away with knot count and silk qums and forget if they like the rug $5,000 worth. The value of the rug will be determined by how popular the design, colors are, but your liking has to be part fo the equation. Rugs are valued at X amount per sq ft. A 3X5 is a small rug even for a silk qum. In my opinion a rug for over $300 per sq ft (the amount the dealer is asking) better be something special and I do really see that in the rug you've shown.
I'll attach some pictures of two silk on silk qum. I have just taken them to a certified appraiser, Atiyeh Bros if you want to google them, to get an insurance appraisal. The amount the rug is worth in my eyes would be somewhere about 25% to 35% of the appraisal.
if you would like me to I will tell you how much they were appraised for.
I would be awful leary to take one dealer's opinion on a $5,000 rug All dealers will let you take the rug home. Many dealers will act as if they are your friends so you trust them.
the rist two pictures of a qum with circular pattern represents the dome fo a mosque and is 3X5 The second is a 4X6. You will notice the signature of a qum rug, as far as I know, usually startes with Qum Iran and I don't see that on your rug.
Anyway for what it's worth see what you think of the pictures if they are better or worse than yours. I won't take the space to show knot count, but they are both around 600.
I gauge the mosque dome rug to be worth $3,000 and the larger, but not as special rug to be worth $2400.
Again other might have other opinions but atleast the pictures will give some comparisons.
Let me know what you think of them.
btuma6 attached the following image(s):