No they don't. You are suggesting taking normal trains OOS during the peak and replacing them with HC trains. All SWT is have HC sets for HC routes, which FGW already have
South West Trains 450/5s
Also bear in mind that the SWT 450/5s are used not only during peak times but also at off peak times as well as part of South West Trains' strategy to meet their new franchise's requirement for additional passenger capacity on the Windsor Lines from Waterloo to Windsor, Weybridge via Chertsey and on the Hounslow Loop.
Now while the SWT modifications do give a net loss of 16 seats, it does however present a increase in standing capacity and should result in much better conditions for standing passengers in the peaks on the Windsor services.
In January 2008, 26 450/0 sets were modified and re-numbered in the 450/5 series, for use on services between Waterloo and Windsor, the Hounslow Loop Line, as well as between Waterloo and Weybridge. They have had their first class seating removed and replaced with 2+3 formation standard class seating and some other seats have been removed to provide more standing capacity; extra handrails have also been provided. The numbers modified are 450043 to 450070, which have become 450543 to 450570 respectively and display the letters 'HC' above the unit number on the front of the sets. The modifications have been carried out at Bournemouth.
First Great Western HSTs
As to the FGW HSTs, I've use them a number of times and find them to be comfortable and they have delivered improvements to the sets such as:
new standard seats designed to encourage comfortable posture and provide extra legroom.
power points for laptop and mobiles are located between seats and improved lighting and new toilets have been fitted throughout.
first class passengers now benefit from full leather reclining seats (which was a first for a UK train operator) with two power points at table level and travel in style with at seat service provided by the onboard First Class Host..
hooks for jackets are available in Standard and First, emergency lighting and new carpets have been installed throughout with improved disabled facilities including two wheelchair spaces in coach E and priority seats with extra legroom in each standard carriage.
The interiors of the sets were overhauled as part of a £63 million Refresh programme of the 53 HSTs, and the result of more than two years design work by ex-Porsche and Eurostar designer, Michael Rodber.
Note the power cars had also undergone a major £80 million modernisation programme with new MTU engines which will not only increase reliability, but will reduce Co2 emissions by 64%.
So in short, all Klambert is suggesting will make it uneconomical to carry out as no company in their right mind will want their stock to be sitting around idle when it can be used to run services, FGW don't have the luxury of basically having two types of HSTs as the HSTs are and need to be diagrammed to work any of the HSS workings.
I was counting them in my head in multiples of 6, it's not like I don't look at them every day, no excuse!