Seems like there are no SOLD listings available on REVERB. They only way to find them is to do a google search for item X, look at the photos of them and then select any that were from REVERB.
Yes they do make it harder. You can get to them if they are on your watch list, and sometimes via other search methods. Reverb have tried to be clever by supplying summary statistics on similar cymbals which have sold. Their summary statistics are not very reliable because the programmers use faulty data in their modelling and they don't appear to use all the relevant factors. The worst case I noticed is their prices for K Zildjian Istanbul cymbals fail to distinguish between Old Stamp and Intermediate plus New Stamps which is the single biggest factor in predicting prices (after diameter). So they clearly have an inadequate model.
Their price guide for 1960s K Zildjian Istanbul 20": https://reverb.com/price-guide/guide/1969-k-zildjian-20-ride-istanbul-1960s
$720 - $1375
My price estimates with separate production eras: http://black.net.nz/old-k/old-k-prices.html#20
[img]http://black.net.nz/old-k/pricing/K20-price-by-era.png[/img]
show the difference in price distributions between Old Stamps (up to 1959), Intermediate Stamps (1959-1966), and New Stamps (1967-1977). As you can see, calling them "1960s" includes Intermediate Stamps and some unknown proportion of New Stamps. All based on what the seller said it was not what it really was. This is partly why their historical analysis shows an $1800 sale for a 20" in fair condition next to a $675 sale for one in excellent condition, next to a $515 sale for one in good condition.
As far as faulty data goes, they take the seller's word (as in just use the text) provided to identify brand, model, production era, condition, etc. That is a classic example of garbage in garbage out. How big is the problem? 25% or more cymbals tend to be misidentified (or not identified) correctly as to decade based on my research on eBay. I haven't looked at Reverb specifically in terms of classification/identification error rates, but the other day somebody asked me about a K Zildjian Istanbul cymbal listed and it was incorrectly identified as Old Stamp when it was Intermediate, and while I was there I quickly found a second cymbal identified as Intermediate which was an Old Stamp. That's two incorrect ids out of 9 x 20" and 2 x 22" currently on offer...so...about 20% wrong.
Note I'm not just picking on Reverb and their pricing analysis. Ebay historic pricing data and graphs suffer from the same garbage in garbage out and fitting of models which don't always include the key factors which influence price. You might say this is just an old guy PhD in Statistics pointing out the poor level of analysis done by "big data" script kiddies in big corporations. You would be correct, but that doesn't make their methods and results sound. ;)
On ebay : seems even for BIN items where offers were taken and you know that the asking price wasn't fetched that the listing shows that the asking price is what the item sold for.
Yes eBay changes last year (at least -- could be 2 years ago) mean that once some kind of offer is made and accepted they show the wrong price (based on the initial asking price not the price which was accepted). The is to the detriment of my pricing research. I only use price data from those kinds of sales when I need to, and as my sample sizes grow I don't need to very often. They are filtered out in most of my analyses. When I do use them I know they are an upper bound on price.
See also my comments here:
http://www.vintagedrumforum.com/showthread.php?p=434083#post434083
for other recent detrimental changes.