Are a Carter AVS 4638 and 4640sa similar?

[1969chargerrtse]

I want to piece together a stripped down 4640sa carb ( missing parts the 4638 has ).  I found a 4638 carb that by pictures looks very close to exact.  The 4640 is for a Auto 440 69 Charger with A/C and the 38 is for a 69 Road runner 383 auto with A/C. Any chance someone here is a carb nut and knows that the 38 and 40 are almost the same except throttle or jet size.
Picture with air cleaner stud is 4638 for 383.
Carb on box is 4640 for 440
The 4640 carb here is not the stripped down carb I know of, this seller wants 300.00 and it needs to be rebuilt and not guaranteed complete.
I have several angles of both and they look the same.

[62 Max]

Only difference is jetting,primary bore size and booster assemblies.

[1969chargerrtse]

Only difference is jetting,primary bore size and booster assemblies.

Cool, but what are the booster assy?  So flaps, linkgage and the outside shell are the same?

[tan top]

the throttle bores are a different size , jets & metering rods  ,  also the idle mixture screws , they are the only carb that has the long ones with a spring for tention  , think the top plate could interchange , & all  linkage  ,  avs 4640SA   are difficult  to come by   , tonys parts has one  ,  bought a spare from him also years ago , to rebuild  my original that had worn throttle shafts

http://www.tonysparts.com/BrowseResults.asp

[1969chargerrtse]

Thanks for your help people, and tan top that answered all the questions I PM'd him.  I bid 125.00 on the carb listed for 300.00 and won it.  So I ordered a rebuilt kit and wish me luck. I'll post info and pictures on my restoration thread as I move along. The issue with the Eldelbrock on the car now is that the throttle position is different than original and not allowing full kickdown performance. Original is better in my book.  
I emailed Tony's parts and they have the carb for 155.00  when I asked them if they could email me pictures, they vanished.  So they can keep it. 

[chargerlarry1980]

So how well does this piece perform? Just found out thats whats on top of my engine. Going to have it rebuilt and give it a go. Will this work with my stock linkage? Its a 72 with a 71 440.