Birth look up - Johnston twins 1889

[Chicago61]

Hello - need help locating a birth record:

George Alexander Johnston, born 17 Oct 1889 in Belfast

According to 1901 census (and several US records), he has a twin brother, Joseph.  The parents are James Johnston and Margaret McKay.  I have searched the LDS Pilot Site and RootsIreland site.  No apparent matches for George, but I did find a match when using Alexander.  Is there anyway to verify this is the correct record before I order it?
 
Alexander Johnston
Oct - Dec 1889 Belfast Registration District
Volume 1, Page 219

Thank you for any help or guidance you may be able to provide.

[aghadowey]

For reference here's the family in 1901-
www.census.nationalarchives.ie/pages/1901/Antrim/Shankhill/Browness/947864

There's also a birth registration for a Joseph Johnston Oct./Dec.1889 Belfast registration district, volume 1 page 219

[Chicago61]

Thank you for your response.  I have several years of experience doing genealogy research, but this is the first attempt working outside of the US.  I am still discovering what resources are available. 

Since I haven't worked with this record index until now, I wasn't sure if there was a way to actually confirm I had found the correct birth record.  Do you think since the listing for "Joseph" is found on the same page as "Alexander" that it is probably the right one?

Do you know if  a subscription to one of the online databases (AncestryIreland, EmeraldAncestors, or RootsIreland) will allow me to see the entire record online so I can verify it is the correct one?  I will also need to look up marriage and death records, so I guess my real question is which of these sites (in your opinion) have the most complete records?

Eventually I will need to order certified copies of the records once they are all located. 

Thanks again for your help and interest.

[aghadowey]

Irish birth, marriage and death certificates are not viewable online.

There are a few topics in Resources which might be of interest-
Introduction to Irish Records
Ordering Certificates for N.I. counties